1. Field of the Invention
The present invention relates to a capacitive touch panel, and more particularly to a capacitive touch panel capable of performing three-dimensional capacitance detection.
2. Description of the Prior Art
Generally speaking, a capacitive touch panel is composed of a capacitance array and a capacitive sensor readout circuit. The conventional design for capacitance array includes a capacitance formed by conductive patterns on the upper surface and the lower surface of the touch panel, in which the conductive patterns on the upper surface are complementary to conductive patterns on the lower surface. The touch panel is operated via generating a capacitive effect as soon as a user's finger or a conductor touches and determining the position of the finger or the conductor by variance in capacitance values. The capacitive touch panel utilizes the variance in capacitance values to detect whether human touch is present or not.
Basically, capacitive touch panels differ in the capacitance values formed by various design patterns. Conventional arts achieve the maximum sensitivity for capacitance value by adopting opposite patterns on the upper and lower layers. In case of opposite patterns on the upper and lower layers, the maximum detecting sensitivity for vertical capacitance is achieved and accompanied with poorest horizontal capacitance detection, however. Hence, the conventional arts may only be used for vertical capacitance detection.
In addition, the touch panel adopting ITO (tin-doped indium oxide) wires increases its resistance value in direct ratio as the panel dimension increases. Also, patterns on the upper and lower surfaces are complementary for achieving the optimal detecting sensitivity; therefore, the touch panel may be not used for both sides, or otherwise, the sensitivity would decrease abruptly.
To sum up, it is highly desirable to develop a touch panel capable of performing double-faced detection and may be applied in large dimension touch panel with high sensitivity.